[en] Thin Cr₂O₃(0 0 0 1) layers are formed by oxidation of a Cr(1 1 0) single crystal. This surface is further modified by growing an epitaxial ultrathin V₂O₃(0 0 0 1) film by reactive vapor deposition. Synchrotron based soft-x-ray photoemission spectroscopy and x-ray photoelectron diffraction are used to characterize the surface layers of these two corundum-structured oxides. By comparison of experimental XPD patterns with simulated electron multiple scattering calculations, two distinctively different surface terminations are extracted for the two oxides. While for V₂O₃ we confirm the previously proposed vanadyl-terminated surface structure, we propose a new surface structure for Cr₂O₃ that consists of excess chromium atoms occupying interstitial sub-surface sites. (paper)